Sir David Nicholson should resign as chief executive of the NHS. Yesterday, appearing before the health select committee, he admitted to MPs that he was “absolutely” part of the culture that led to appalling standards of care at Stafford Hospital, causing hundreds of deaths. Yet, despite being head of the strategic health authority that oversaw the hospital in 2005, he refuses to stand down from his present job. His obstinacy sends the wrong message to an institution that desperately needs greater accountability.

Sir David insisted that even though he always inspected hospitals and investigated quality of care, Mid Staffs was not put on the problem list and the “excessive” number of deaths at the hospital was not brought to his attention. He also candidly conceded that the NHS had “lost focus of what was really important to patients” and articulated the common suspicion that the emphasis placed by Labour on achieving targets was part of the problem.

Regardless of whether or not he was personally compromised by the nightmare at Mid Staffs, Sir David must take responsibility for the grotesque failings of the organisation that he now heads. In any private organisation, such a scandal would have led to mass firings or resignations at a senior level – and probable prosecutions. The NHS – in which potential whistleblowers are gagged and complaints too often ignored – can be treated no differently if public confidence is to be restored. It is true that some executives have already gone, but that does not mean justice has been done. Martin Yeates, the former chief executive of Mid Staffs, resigned in 2009 and walked away with £400,000.

Of course, taking responsibility should not stop with Sir David. What have the Labour politicians who oversaw the flawed targets policy to say for themselves? And what about the individual hospital staff whose cruel behaviour – food and water were put out of the reach of the sick and screams for pain relief were ignored – betrayed the trust of patients? It is time that the country moved beyond the sepia-tinted idea that nurses and doctors are “angels”, or that the NHS is morally beyond reproach and should be immune from fundamental reform. A report published yesterday found that even though health spending has tripled in the past 20 years, Britain has actually fallen down the international league table when it comes to life expectancy.

The establishment has failed to grasp the scale of the public’s horror at what happened in Mid Staffs. It has closed ranks to defend its own. But power comes with responsibility, and accountability. Sir David must go.